What's different about inspecting a townhouse or semi-detached home?

Updated October 2026 · By Gerardo Lucero, Certified Professional Inspector (CPI)

First question: what exactly are you buying?

Two townhouses can look identical from the street and be completely different on paper. Before thinking about the wall or the roof, find out which of these you're looking at. The listing and the Agreement of Purchase and Sale should say, and your lawyer will confirm it on title.

If it's a freehold townhouse or semi

You own the house and the land under it, with no monthly fee. You're responsible for everything, including your half of the roof and your side of the shared wall. Repairs where the two homes meet, such as roof flashing or a shared fence, usually need a conversation with the neighbour. Check for easements too, like a shared or mutual driveway.

If it's a condo townhouse (standard condominium)

You own your unit and pay monthly fees to a condominium corporation. Depending on the declaration, the corporation may be responsible for items like the roof, windows, exterior walls and grounds, and it funds them through the reserve fund. Your lawyer reviews the status certificate. The inspection still matters for what's inside your unit; see my guide on whether you need an inspection for a condo.

If it's a POTL (parcel of tied land)

Common in newer GTA developments. You own a freehold house and lot, but it's legally tied to a common elements condominium that owns shared items such as private roads, walkways or visitor parking. You pay a monthly fee for those, but the house itself, roof included, is yours to maintain. For new POTL homes, Tarion is clear that the home has warranty coverage but the common elements do not.

What's different about the inspection itself

The party wall and the attic fire separation

Ontario's Building Code generally requires the wall between attached homes to be a firewall or, in homes where no unit sits above another, a fire separation with at least a one-hour fire-resistance rating. It must run continuously from the footings to the underside of the roof deck, with any gap at the top tightly filled with mineral wool or non-combustible material. In the attic, I look for holes, missing drywall, open gaps at the roof deck and penetrations from ducts, pipes or wires. As a carpenter who has renovated GTA homes since 2009, I know how easily a later renovation or a new pot light can cut through that barrier.

Shared roofs and flashing

Often one owner replaces their half of the roof and the neighbour doesn't. The joint where new shingles meet old ones is a classic leak point, so I look closely at it from safe vantage points and in the attic below.

Drainage between units

Narrow side yards, shared swales and downspouts that discharge toward the next house can send water to the wrong foundation. I trace where the water goes.

What I can't see

I inspect your home, not the neighbour's. I can't enter the attached unit, and a finished basement can hide the party wall. Any limits are written in the report.

What it costs

A mid-unit townhouse is $500; a semi-detached or end-unit townhouse is $550, because there's more exterior wall and roof edge to inspect. See the full cost guide for details.

Looking at a townhouse or semi in Vaughan or anywhere in the GTA? Book your inspection here.

Sources

• www.condoauthorityontario.ca
• tarion.com
• markhammuseum.ca
• markhammuseum.ca

More guides

• How long does a roof last in Ontario, and how do I know it needs replacing?
• What causes attic problems like ice dams, frost and mould?
• How old is too old for a furnace, A/C or water heater, and what about rental contracts?
• How do gutters, downspouts, grading and a sump pump keep water out of my basement?
• What should I check at my new-home PDI with the builder?